1. Field of the Invention
The present invention relates to a display driving apparatus for driving a display panel and a display apparatus that comprises the display driving apparatus and displays an image by driving the display panel.
2. Description of the Related Art
As display panels used for liquid crystal display apparatuses, simple matrix display panels and active matrix display panels are known. According to an active matrix display panel of these display panels, scanning lines (gate lines) intersect signal lines (source lines) at right angles on the display panel, and pixel electrodes are arranged near the intersections between the gate lines and the source lines through thin film transistors (to be referred to as TFTs hereinafter). Display pixels are formed by filling the spaces between these pixel electrodes and a counter electrode facing them with a liquid crystal. Gradation signals are applied to display pixels set in the selected state by scanning signals input through gate lines to change the aligned state of the liquid crystal, thereby displaying an image.
In some form of mounting a display driving apparatus for driving such a display panel on the display panel, semiconductor devices such as a gate driver for driving gate lines, a source driver for driving source lines, and the like are mounted on one edge side of the display panel. That is, in this form, semiconductor devices such as a gate driver and a source driver are mounted in non-display region on the lower edge of the display panel, part of the lower edge of the board of the display panel on a side on which the pixel electrodes are formed is made to protrude, and the source and gate drivers are amounted on the protruding portion. This makes it possible to decrease the widths of non-display regions of the display panel on which interconnections extend in the horizontal direction.
It is generally known that in a liquid crystal display apparatus, the magnitude of a signal voltage applied to the pixel electrode of a display pixel at a trailing edge of a scanning signal input to a TFT becomes equal to a voltage value smaller than the voltage value of the gradation signal output from the source driver by a feedthrough voltage ΔV proportional to the amplitude of the scanning signal. In the arrangement in which the source and gate drivers are mounted on one edge side of the display panel as described above, interconnections for connecting the respective output terminals of the gate drivers to the respective gate line terminals formed on a side edge of the display panel are routed along a side edge of the display panel. The lengths of interconnections (interconnection lengths) vary depending on whether the interconnections are located on a near side or far side of the gate driver. These differences in interconnection length produce differences in interconnection resistance. Due to the differences in interconnection resistance, scanning signals input to display pixels differ in magnitude Vg for each row, resulting in differences in feedthrough voltage ΔV for each row.